The great route was that which led from Venice over the Brenner and up the Rhine to Bruges; and this route became the long red line of municipal development, along which - in Lombardy, Germany and Flanders - the great towns of the middle ages sprang to life.
The centre of the spots on the grapes becomes darker as the disease advances, and a red line appears dividing the dark brown border into an outer and an inner rim and giving a very characteristic appearance to the diseased plant.
At one point on the plateau "the 27th (Inniskillings) were lying literally dead in square"; and the position that the British infantry held was plainly marked by the red line of dead and wounded they left behind them.
Another difficulty, the concealment of the inner core of copper which was seen as a thin red line when a cut edge was exposed, was met about 1784 by George Cadman, who adopted the practice of soldering on an edging, generally ornamented, of solid silver so as to cover the junction, and the presence of this is one of the trustworthy tests by which genuine Sheffield plate may be recognized.
The eastern boundary of this northern section of Baluchistan is the " red line " at the foot of the frontier hills, which defines the border of British India.